TABLE OF CONTENTS IP development and applications. The DSMC method (Bird 1994) is one of the most successful numerical approaches for simulating rarefied gas flows. With appropriate outflow boundary conditions, it can also be used to simulate microflows. However, the statistical scatter associated with DSMC prevents its further applications to microflow of extremely low speeds. The information preservation (IP) method has been developed to overcome this problem of DSMC.
Fan and Shen (1998) first proposed an IP scheme for low-speed rarefied gas flows. Their method uses the molecular velocities of the DSMC method as well as the preserved information velocities that record the collection of an enormous number of molecules that a simulated particle represents. The information velocity is based on an inelastic collision model, and sampled in the same manner as that for the macroscopic flow velocity. IP has been applied to low-speed Couette, Poiseuille, and Rayleigh flows in the slip, transition and free-molecular flow regimes with very good agreement with the corresponding analytical solutions (Fan and Shen 2001). They showed that the IP scheme could reduce computational time by several orders of magnitude compared with a regular DSMC simulation. This scheme has also been applied in the simulation of low-speed microchannel flows (Cai et al. 2000) and the flow around a NACA0012 airfoil (Fan et al. 2001) with isothermal wall conditions.
The model formulation described in the above IP applications is not general. Sun and Boyd (2002) developed a general two-dimensional IP method to...
